Doc: update Qt Creator external pages

Removed links to obsolete pages (some pages were combined and
some were removed), added links to new pages, and changed a title.

Change-Id: Iaf0e3adf2edaf048a8bb7e26b3cfd45c4680de2d
Reviewed-by: Jerome Pasion <jerome.pasion@digia.com>
Don't hardcode devicePixelRatio to 1.

This code path can and will be hit during app startup,
and can result in low-resolution images being used
on high-dpi systems.

Use qApp->devicePixelRatio() instead, which is more
likely to be correct.

Change-Id: Ic881cfedd8e962037d2d4af4a1242f590d56c194
Reviewed-by: Gabriel de Dietrich <gabriel.dedietrich@digia.com>
Reviewed-by: Jens Bache-Wiig <jens.bache-wiig@digia.com>
Clarify Q_INIT_RESOURCE in relation to namespaces

The constructor functions generated by rcc are put in the global namespace.
As there is no way to forward-declare a function in the global namespace
from within another namespace, Q_INIT_RESOURCE must always be called from
the global namespace.

Change-Id: I8b8b9451271cf2f9147164696a6df7615678ab03
Reviewed-by: Jerome Pasion <jerome.pasion@digia.com>
iOS: Remove unused QIOSWindow methods for getting effective width/height

Change-Id: Ifdfd5881822bf56f2c8ab0742a0e257e2bd61533
Reviewed-by: Morten Johan Sørvig <morten.sorvig@digia.com>